1. Field of the Invention
The present invention relates to an upside-recessed-and-headrest-storage type of seat which is formed with a headrest storage recession in a top portion of the seat back thereof, thereby enabling a user to retract and store an entire body of headrest in that headrest storage recession, lest the headrest should project from the seat back, so as to provide a unitary appearance of seat back, as if the headrest was an integral part of the seat back. More specifically, the invention is directed to a structure of the seat back in this particular kind of seat.
2. Description of Prior Art
There has been known a seat of the type wherein the seat back thereof has a headrest storage recession defined in the top portion thereof, or what can be described as an upside-recessed-and-headrest-storage type of seat (this term will be used hereinafter), which allows an entirety of headrest to be stored in the headrest storage recession, as if the headrest itself was embedded in the top of seat back thereof and became an integral part of the seat back, while on the other hand allowing the headrest to be raised from that storage recession to a desired level for supporting a head of user.
Such upside-recessed-and-headrest-storage type of seat has been applied to vehicle or automotive seats, and in particular applied to a fold-down vehicle seat, a retractable vehicle seat, and the like, which is collapsible into a small-sized configuration. For, a whole of the headrest can easily be lowered to and stored in the headrest storage recession of the seat back, thus completely preventing projection of the headrest from the top of the seat back to thereby avoid interference with any other surrounding items and things.
Recently, in view of increasing demands for small-sized and thin mode of the fold-down vehicle seat or retractable vehicle seat, each of headrest and seat back thereof inevitably requires further reduction in thickness. Those demands and requirements are also extended to the aforementioned upside-recessed-and-headrest-storage type of seat with a headrest storage recession in the top portion of seat back thereof. In particular, this kind of seat actually require reducing a depth of the headrest storage recession at the seat back top thereof in view of the foregoing demands.
In order to meet such recent demands, by way of example, the Japanese Laid-Open Patent Publication No. 2002-124793 discloses a seat back structure of this kind of seat having a headrest storage recession in the seat back top thereof, wherein a rigid and thin back board is securely attached to an entirety of backward surface of seat back so as to cover a backward side of a headrest storage recession defined in the seat back top, while on the other hand, a thin cover plate member is securely attached to a forward side of that headrest storage recession and juxtaposed on the corresponding upper local area of the afore-said back board. In that way, the thickness of the recessed headrest storage region is reduced.
However, the foregoing prior art has been found defective in that the back board and cover plate member are provided independently of each other, which requires an increased number of component parts and much more labor to assemble those two elements together, and also raises the problem of troublesome maintenance and control of the relevant component parts. Further, putting together such separate back board and cover plate member inevitably leaves a connection line there between on a finished seat back, which is exposed outwardly and viewed as an objectionable spot that impairs an aesthetic appearance of the seat back.